CA Ins Code Section 10709

(a)

No health benefit plan may exclude late enrollees from coverage for more than 12 months from the date of the late enrollee’s application for coverage. No premiums shall be charged to the late enrollee until the exclusion period has ended.

(b)

A carrier providing aggregate or specific stop loss coverage or any other assumption of risk with reference to a health benefit plan shall provide that the plan meets all requirements of this section concerning late enrollees.